They do have wine tastings, and if the ship has a wine bar you will find the bar staff there helpful. Some are better at it than others. Sadly, many cruise lines have eliminated dining room wine stewards.
It just hit me that I recall something about RCI rethinking the dining room wine service. Maybe it was bar service in general. But there was some discussion within the past year. That is another question for the concierge. I do specifically remember reading about taking the wine service off the waiter's list of duties. I just don't remember who would pick it up.